The aerodynamic design of a BWB has several major challenges compared to the conventional ...

148 Pages·2014·5.93 MB·English

by  Alejandro López Telgie

Design and analysis of the DelFFi
solar energy supply
Alejandro Ignacio Lopez Telgie

s
i
s
e
h
T

c
S
M

MSc Thesis
Design and analysis of the DelFFi solar energy supply
By
A.I. Lopez Telgie

In partial fulfilment of the requirements for the degree of
Master of Science
in Aerospace Engineering
At the Delft University of Technology

(Delft, July 2014)

Student number: 1539191
Supervisor: ir. Jasper Bouwmeester, TU Delft
ii

Design and analysis of the DelFFi solar energy supply Alejandro I. Lopez Telgie
To the loving memory of my father
Alejandro Antonio Lopez Devaud
1961-2011

Design and analysis of the DelFFi solar energy supply Alejandro I. Lopez Telgie

Abstract
The present thesis deals with the design and analysis of the solar energy supply for the DelFFi nano-
satellites. The DelFFi project is parts of the QB50 mission, led by VKI, that intends to launch 50
CubeSat to 350-400[km] altitude in 2016, to carry in situ research in the lower thermosphere. This
kind of research has never been done in the past, nor envisioned in the future. Hence, unique
challenges are faced by the participating teams.
The research was divided into three parts. Part I deals with research a photovoltaic and
semiconductors theories, which lead to the understanding of the solar cells working principles. It was
followed by an assessment of the available hardware useful for the DelFFi design. Part II deals with
Launch and Early Operations of Delfi-n3Xt, predecessor or DelFFi launch on November 21st, 2013, as
well as telemetry analysis of the EPS. This lead to lessons learned that could are used in Part III which
synthesizes the previous and includes a proposed design of the DelFFi power subsystems. This
includes the EPS board and Battery selection, as well as a detailed layout of the solar cells within the
panels of the proposed deployment configuration. The later, was used to assess the available power
for satellite operations through a model using ESATAN-TMS and Microsoft Excel.
Based on the available hardware, and follow up analysis, solar cells assemblies as well as a COTS EPS
board and Battery pack have been selected and price quotes are available for procurement. The
LEOPS experience as well as the detailed documentation review and analysis, done for Delfi-n3xt,
lead to several lessons learned which are employed in the proposed design for DelFFi. The key ones
are not relying on the ADCS for the power performance, which lead to a satellite with cell on every
face possible as well as double sided deployable panels; a operational balance of the power budget
through duty cycling of the subsystems in different operational modes; and a design which increases
the overall EPS efficiency from ~63% on Delfi-n3Xt to ~70% on DelFFi.
Over the last months an almost full life cycle in a satellite mission has been experience: design,
launch, operations, and selection of components. The proposed design remains to be manufacture
once the selected hardware arrives on site, and further testing will improve the accuracy of the
model used for assessing the available power.
The proposed solar energy supply system is and improvement of the one on its predecessor with
increased efficiency and design for a mission in a very particular region of the Atmosphere, which will
deliver new science returns.

Design and analysis of the DelFFi solar energy supply Alejandro I. Lopez Telgie
vi
“If we knew what it was we were doing,
it would not be called research, would it?”
Albert Einstein

“When people cooperate they use less resources.”
Yves Morieux @ TED San Francisco, October 2013

Acknowledgments
I would start by acknowledging my family and friends, because without their unconditional support
this would have never been possible.
My supervisor ir. Jasper Bouwmeester, who’s door was always open for a “short question”, provided
crucial feedback for this thesis. As well as Nuno for insight in electronics.
Regarding my colleagues, I’ll like to thanks the DelFFi team and the other students of the MSc room,
as they made the day to day over the last months, very interesting. Special note goes to Remco S.
due to his support in LyX and IT in general.
My sponsor Becas Chile, for the scholarship that helped financing my MSc study.

I wish you all success,

Alejandro I. Lopez Telgie
Delft, July 2014

Design and analysis of the DelFFi solar energy supply Alejandro I. Lopez Telgie
Table of contents
ABSTRACT....................................................................................................................................... V
LIST OF FIGURES ............................................................................................................................... IX
LIST OF TABLES ................................................................................................................................ XII
NOMENCLATURE ............................................................................................................................ XIV
INTRODUCTION ................................................................................................................................ 1
1.1 PROJECT CONTEXT ........................................................................................................................... 1
1.2 THESIS OBJECTIVES ........................................................................................................................... 2
1.3 THESIS OVERVIEW ............................................................................................................................ 3
PART I THESIS CONTEXT ................................................................................................................ 5
PHOTOVOLTAIC THEORY AND SOLAR CELL PRINCIPLES ................................................................................. 7
2.1 PHOTOVOLTAIC THEORY .................................................................................................................... 7
2.2 SEMICONDUCTORS ........................................................................................................................... 7
2.3 SOLAR CELL, ASSEMBLY, AND CHARACTERIZATION .................................................................................. 9
STATE OF THE ART ........................................................................................................................... 15
3.1 CUBESAT POWER REQUIREMENT ...................................................................................................... 15
3.2 COMMERCIAL OF THE SHELF SOLAR PANELS FOR CUBESATS ................................................................... 15
3.3 SOLAR CELLS ................................................................................................................................. 17
3.4 NEED FOR COVER GLASS .................................................................................................................. 20
3.5 SOLAR CELL SELECTION TRADE-OFF .................................................................................................... 22
PART II DELFI-N3XT ANALYSIS ..................................................................................................... 25
DELFI-N3XT .................................................................................................................................. 27
4.1 DELFI-N3XT OVERVIEW ................................................................................................................... 27
4.2 LAUNCH AND EARLY OPERATIONS EXPERIENCES ................................................................................... 30
EPS TELEMETRY DATA ANALYSIS ........................................................................................................ 35
5.1 TOTAL SOLAR ARRAY POWER ............................................................................................................ 35
5.2 VARIABLE VOLTAGE BUS .................................................................................................................. 37
5.3 REGULATED 12V BUS POWER CONSUMPTION ..................................................................................... 39
5.4 BATTERIES .................................................................................................................................... 43
5.5 ECLIPSE TRIGGERING ANALYSIS ......................................................................................................... 46
5.6 CRITICAL ROTATION ........................................................................................................................ 47
LESSONS LEARNED .......................................................................................................................... 51
6.1 OPERATIONS ................................................................................................................................. 51
6.2 EPS ............................................................................................................................................. 52
PART III DELFFI ELECTRICAL POWER SUBSYSTEM ......................................................................... 55
DELFFI EPS ARCHITECTURE ............................................................................................................... 57
7.1 EPS ELEMENTS .............................................................................................................................. 57
Design and analysis of the DelFFi solar energy supply Alejandro I. Lopez Telgie
viii
7.2 EPS REQUIREMENT ANALYSIS ........................................................................................................... 58
7.3 EPS SELECTION .............................................................................................................................. 61
7.4 BATTERY CONFIGURATION SELECTION ................................................................................................ 65
7.5 EPS INTERFACES ............................................................................................................................ 69
AVAILABLE ELECTRICAL POWER........................................................................................................... 75
8.1 ANALYSIS SOFTWARE ...................................................................................................................... 75
8.2 ANALYSIS CASES DEFINITION ............................................................................................................ 76
8.3 DATA ANALYSIS/PROCESSING ........................................................................................................... 77
8.4 DELFFI SOLAR PANEL CONFIGURATION ALTERNATIVES .......................................................................... 80
8.5 DETAILED ANALYSIS OF LOW WING DEPLOYMENT CONFIGURATION ......................................................... 82
8.6 DELFFI CONSUMED POWER BUDGET ................................................................................................. 89
8.7 CLOSING REMARKS ......................................................................................................................... 92
DELFFI SOLAR PANEL LAYOUT AND DEPLOYMENT SYSTEM ......................................................................... 95
9.1 VOLUME AVAILABLE FOR THE PANEL PCB DESIGN ................................................................................ 95
9.2 INTERNAL SOLAR PANEL PCB LAYOUT ............................................................................................... 97
9.3 SUMMARY OF REQUIREMENTS ......................................................................................................... 98
9.4 LOADS .......................................................................................................................................... 99
9.5 SOLAR PANEL CONFIGURATION AND CELLS ALLOCATION ........................................................................ 99
9.6 DEPLOYMENT MECHANISM (HINGE) ................................................................................................ 101
9.7 TEC1D CELL ALTERNATIVE ANALYSIS ................................................................................................ 102
9.8 CLOSING REMARKS ....................................................................................................................... 106
CONCLUSIONS AND RECOMMENDATIONS ............................................................................................. 107
10.1 CONCLUSION ............................................................................................................................... 107
10.2 RECOMMENDATIONS AND FUTURE WORK ........................................................................................ 108
APPENDIX ................................................................................................................................. 109
A. TECSTAR TECT1D SOLAR CELL ASSEMBLIES SPECIFICATIONS ............................................................... 111
B. AZURSPACE SOLAR CELL ASSEMBLIES ........................................................................................... 113
ELECTRICAL DETAILS.................................................................................................................................. 113
MECHANICAL INTERFACE ........................................................................................................................... 115
C. DELFI-N3XT TELEMETRY ANALYSIS FLOWS ..................................................................................... 116
TOTAL SOLAR ARRAY POWER ...................................................................................................................... 116
VARIABLE VOLTAGE BUS ............................................................................................................................ 116
REGULATED 12[V] BUS POWER CONSUMPTION ............................................................................................. 116
D. DELFI-N3XT SUN SENSOR MECHANICAL INTERFACE DRAWINGS ........................................................... 117
E. GAMALINK ANTENNAS DIMENSIONS ............................................................................................ 118
F. DELFI-N3XT HOLD DOWN AND RELEASE MECHANISM LAYOUT ............................................................ 118
G. ISIS ANTENNA DEPLOYMENT MECHANISMS MECHANICAL INTERFACE ................................................... 119
H. DELFFI SOLAR PANEL LAYOUT MECHANICAL DRAWINGS.................................................................... 120
I. FIPEX TEMPERATURE SENSORS KEEP OUT AREAS ............................................................................... 123
BIBLIOGRAPHY .............................................................................................................................. 124

Design and analysis of the DelFFi solar energy supply Alejandro I. Lopez Telgie